1. Field of the Invention
This invention relates to location of transmission facilities and more particularly to the location of transmission facilities, such as cellular phones, in correctional institutions and controlling their use.
2. Background
There are many facilities, such as government buildings, and in particular correctional facilities, such as prisons, that do not permit cellular phone usage on the premises or even possession of cell phones in the premises. Finding and preventing usage of cell phones and other transmission facilities is difficult, and a need exists for improved methods of locating such devices, as well as a need for detecting such devices upon ingress to a facility.